Economic theory the ideas and priniciples that aim to describe how economies work. 

Economic theory mainly describe about principles of economics. And also about it's modification that how it's occur in Substitute form.

Economic theory means:
Economic theory refers to the set of principles and concepts that explain how economies work and how individuals and societies make decisions regarding the allocation of resources. It provides a framework for understanding and analyzing economic phenomena and helps economists develop models to make predictions and inform policy decisions.

Principles of economics:
Economic theory comprises the principles of economics, which are the fundamental concepts that guide economic analysis. These principles include:

1. Scarcity: Resources are limited, and individuals and societies must make choices about how to allocate them.

2. Opportunity cost: The cost of choosing one option is the value of the next best alternative that is foregone.

3. Supply and demand: Prices are determined by the interaction of supply and demand in a market.

4. Marginal analysis: Decisions are made by comparing the additional benefits and costs of a specific action.

5. Efficiency: Resources should be allocated in a way that maximizes overall welfare or satisfaction.

6. Trade-offs: Making choices often involves giving up something in return.

7. Comparative advantage: Individuals or countries should specialize in producing goods or services in which they have a lower opportunity cost.

8. Rational behavior: Individuals are assumed to make decisions that maximize their own self-interest.

Descriptive economics:
Descriptive economics is a branch of economics that focuses on describing and analyzing the current state of the economy. It involves collecting and analyzing data to understand economic phenomena, such as GDP growth, inflation rates, unemployment rates, and income distribution. Descriptive economics provides the foundation for economic theory by providing empirical evidence and observations that inform economic analysis.

Economic facts:
Economic facts refer to objective and verifiable information about the economy. These facts can include historical data, such as past GDP growth rates, inflation rates, or trade balances. Economic facts are used as inputs for economic analysis and the development of economic theories. However, economic theory goes beyond facts by providing a framework for understanding and explaining the underlying causes and relationships between economic variables.

In summary, economic theory encompasses the principles of economics, which provide a framework for understanding how economies function. It goes beyond descriptive economics by analyzing the underlying causes and relationships between economic variables. Economic facts are used as inputs for economic analysis but do not encompass the entirety of economic theory.